Desertification is a kind of land degradation in a qui Relatively dry area of land Becomes increasingly arid, losing Typically icts bodies of water as well as vegetation and wildlife. [2] It is caused by a variety of factors, such as through climate change and through the exploitation of soil by human activity. [3] When deserts appear automatically over the course of a planet’s life cycle, then it can be called a natural phenomenon; However, when deserts emerge due to the rampant and unchecked depletion of nutrients in soil that is essential for it to remain arable, then a virtual „soil death“ can be spoken of, [4]which traces its cause back to human overexploitation. Desertification is a significant global ecological and environmental problem . [5]

Definitions

Considerable controversy exists over the proper definition of the term „desertification“ for which Helmut Geist (2005) has identified more than 100 formal definitions. The most widely accepted [2] of these is that of the Princeton University Dictionary which defines it as „the process of fertile land transformation as a result of deforestation , drought or improper / inappropriate agriculture“. [6]
Desertification has been neatly defined in the text of the United Nations Convention to Combat Desertification (UNCCD) as „land degradation in arid, semi-arid and dry sub-humid regions resulting from various factors, including climatic variations and human activities. “ [7]

Another major contribution to the controversy comes from the sub-grouping of types of desertification. Spanning from the very wave yet shortsighted view the „man-made-desert“ to the more broadly less focused type as the „Non-pattern-Desert“ [8]

The earliest known arose after the French colonization of West Africa , when the Committee of Studies commissioned a study on progressive desiccation to explore the prehistoric expansion of the Sahara Desert. [9]

History

The world’s most noted deserts have been formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. Paleodeserts are wide sand seas now inactive Because They Are stabilized by vegetation, some Extending beyond the present margins of core deserts, Such As the Sahara , the Largest hot desert. [10]

Desertification has played a significant role in the human history, contributing to the collapse of several large empires, such as Carthage, Greece, and the Roman Empire, as well as the displacement of local populations. [5] [11] [12] [13] [14] Historical evidence shows that the Mediterranean and the Mesopotamian Valley, and the Loess Plateau of China, where population was dense. [11] [15]

Areas affected

Drylands occupy approximately 40-41% of Earth’s land area [17] [18] and are home to more than 2 billion people. [18] It is already degraded, the total area affected by desertification being between 6 and 12 million square kilometers, that about 1-6% of the inhabitants of drylands living in desertified areas, and that a billion people are under threat of further desertification. [19] [20]

As of 1998, the then-current degree of southward expansion of the Sahara is due to a lack of recent, measurable expansion of the desert in the Sahel at the time. [21]

The impact of global warming and human activities are presented in the Sahel. In this area, the level of desertification is very high compared to other areas in the world. All areas in the eastern part of Africa (ie in the Sahel region) are characterized by a dry climate, high temperatures, and low rainfall (300-750 mm rainfall per year). So, droughts are the rule in the Sahel region. [22] Some studies have shown that Africa has lost approximately 650,000 km² of its productive agricultural land over the past 50 years. The spread of desertification in this area is considerable. [23]

Some statistics have shown that since 1900, the Sahara has expanded to 250 km to the south, covering an additional area of ​​6000 square kilometers. [23] The survey, done by the research institute for development, showed that it is fast growing in the Sahelian countries. Desertification in the Sahel can affect more than one billion of its inhabitants. 70% of the arid area has deteriorated and water resources have disappeared, leading to soil degradation. The loss of topsoil means that plants can not take root firmly and can be uprooted by torrential water or strong winds. [23] [24]

The United Nations Convention (UNC) says that about six million Sahelian citizens would have to give up the desertified areas of sub-Saharan Africa for North Africa and Europe between 1997 and 2020. [23] [24]

Another major area that is being impacted by desertification is the Gobi Desert. Currently, the desert Gobi is the fastest moving desert on Earth; The Gobi Desert swallows up over 1,300 square miles of land annually. This village has been destroyed many villages in its path. Currently, photos show that the Gobi Desert has expanded into the area. [25] This is a major problem for the people of China. They will soon have to deal with the desert as it creeps closer. Although the Gobi Desert is still a distance from Beijing, reports from field studies are large sand dunes only 70 km (43.5m) outside the city. [26]

Vegetation patterning

As the desertification takes place, the landscape may progress through different stages and continuously transform in appearance. Sloped land, desertification can be spread over a large strip of land, known as “ Tiger Bush „. A mathematical model of this phenomenon proposed by C. Klausmeier. [27] One outcome of this observation suggests an optimal planting strategy for agriculture in arid environments. [28]

Causes

The immediate cause is the loss of most vegetation. This is driven by a number of factors, alone or in combination, such as drought, climatic shifts, tillage for agriculture, overgrazing and deforestation for fuel or construction materials. Vegetation plays a major role in determining the biological composition of the soil. Studies have shown that, in many environments, the rate of erosion and runoff decreases exponentially with increased vegetation cover. [32] Unprotected, dry soil surfaces are blown away by the flash floods, leaving infertile lower soil layers than the unproductive hardpan. Controversially, Allan SavoryIt has the ability to control the herds of livestock, to reverse desertification. [33] [34] [35] [36] [37]

Poverty

At least 90% of the inhabitants of drylands live in developing countries , where they suffer from poor economic and social conditions. [19] This situation is exacerbated by land degradation because of the reduction in productivity, the precariousness of living conditions and the difficulty of access to resources and opportunities. [38]

A downward spiral is created in many underdeveloped countries by overgrazing , land exhaustion and overdrafting of groundwater in many of the marginally productive world regions to overpopulation pressures to exploit marginal drylands for farming. Decision makers are understandably able to invest in arid areas with low potential. This lack of investment contributes to the marginalization of these areas. When unfavorable agro-climatic conditions are combined with an absence of infrastructure and access to markets, they are poorly adapted to production techniques and an underfed and undereducated population, most such areas are excluded from development. [39]

Desertification often causes rural lands to become unable to support the same sized populations that previously lived there. This results in mass migration out of rural areas and into urban areas, PARTICULARLY in Africa. These migrations into the cities often cause large numbers of unemployed people, who end up living in slums . [40] [41]

Countermeasures and prevention

Techniques and countermeasures exist for mitigating or reversing the effects of desertification, and some possessing different levels of difficulty. For some, there are numerous barriers to their implementation. Yet for others, the solution simply requires the exercise of human reason.

One of the difficulties that has been proposed, [43] however controversial it may be, is to bring about a cap on the population growth, and in fact to turn this into a population decay, who need to grow their food.

They are socially and environmentally friendly, and they are socially and environmentally beneficial. [44] Another issue is a lack of political will, and lack of funding to support land claims and anti-desertification programs. [45]

Desertification is recognized as a major threat to biodiversity . Some countries have developed Biodiversity Action Plans to counter its effects, particularly in relation to the protection of endangered flora and fauna . [46] [47]

Reforestation is one of the causes of desertification and is not just a treatment of symptoms. Environmental organizations [48] work in places where deforestation and desertification are contributing to extreme poverty . There they focus primarily on educating the local population about the dangers of deforestation and sometimes employing them to grow seedlings, which they transfer to severely deforested areas during the rainy season. [49] The Food and Agriculture Organization of the United Nations launched the FAO Drylands Restoration Initiative in 2012 to draw together knowledge and experience on dryland restoration. [50]In 2015, FAO published the global guidelines for the restoration of degraded forests and landscapes in drylands, in collaboration with the Turkish Ministry of Forestry and Water Affairs and the Turkish Cooperation and Coordination Agency. [51]

Currently, one of the major methods that has been finding success in this battle with desertification. This is known as the Green Wall of China . This wall is a much larger version of what American farmers did in the 1930s to the Midwest dust bowl. This plan was proposed in the late 1970s, and has become a major ecological engineering project which is not predicted to end until the year 2055. According to Chinese reports, there have been nearly 66,000,000,000 trees planted in China’s great green wall. [52] Due to the success that China has found in stopping the spread of desertification. Through their success with their wall, plans are currently being made in Africa to start a „wall“ along the borders of the Sahara desert as well.

Focus on two aspects: provisioning of water, and fixation and hyper-fertilizing soil.

Fixating the soil is often done through the belts , woodlots and windbreaks . Windbreaks are made from trees and used to reduce soil erosion and evapotranspiration . They were encouraged by the development of the 1980s in the Sahel area of Africa .

Some soils (for example, clay), due to lack of water can not be consolidated rather than porous (as in the case of sandy soils). Some techniques as zai gold are then used to allow the planting of crops. [53]

Another technique that is useful is contour trenching . This involves the digging of 150m long, 1m deep trenches in the soil. The trenches are made parallel to the height lines of the landscape, preventing water from flowing within the trenches and causing erosion. Stone walls are placed around the trenches to prevent the trenches from closing up again. The method was invented by Peter Westerveld. [54]

Enriching of the soil and restoration of its fertility is often done by plants. Of these, leguminous plants qui extract nitrogen from the air and fix it in the soil, and food crops / trees as grains , barley , beans and dates are the major most. Sand fences can also be used to control drifting of soil and sand erosion. [55]

Some research centers (such as IRD / ISRA / UCAD Bel-Air Research Center) are also experimenting with the inoculation of tree species with mycorrhiza in arid zones. The mycorrhiza are basically fungi attaching themselves to the roots of the plants. They hereby create a symbiotic relationship with the trees, increasing the area of ​​the tree’s roots (allowing the tree to gather much more nutrients from the soil). [56]

There are many different types of deserts, there are also different types of desert reclamation methodologies. An example for this is the salt-flats in the Rub ‚al Khali desert in Saudi Arabia . These salt-flats are one of the most promising desert areas for seawater agriculture and could be revitalized without the use of freshwater or much energy. [57]

Farmer-managed natural regeneration(FMNR) is another technique that has produced successful results for desert reclamation. Since 1980, this method of reforest degraded landscape has been applied to some success in Niger. This simple and low-cost method has enabled farmers to regenerate some 30,000 square kilometers in Niger. The process raises the need for growing tree growth through selective pruning of shrub shoots. The residue from pruned trees can be used to provide mulching for fields of water. Further, properly spaced and pruned The Humbo Assisted Regeneration Project which uses FMNR techniques in Ethiopia has received money from the World Bank’s BioCarbon Fund, which supports the projects that sequester or conserve carbon in forests or agricultural ecosystems.[58]

Managed grazing

Restoring grasslands store CO 2 from the air into plant material. Grazing livestock, would not eat wander, would eat the grass and grows it would be possible to grow it, to prevent it from growing. [60] A method proposed to restore grasslands with other small paddocks and moving herds to a paddock to one another or to grow more easily. [60] [61] [62] It is estimated that increasing the carbon content of the world’s 3.5 billion hectares of agricultural production would offset nearly 12 years of CO 2 emissions.[60] Allan Savory , a part of holistic management , claims that it is widely blamed for desertification, prehistoric lands, and large areas of the United States are still desertifying. [59]